That would be sooner than previous forecasts used by thecompany and its U.S. partner.

Enbridge and Enterprise Products Partners LP havebeen saying for months that they would boost the capacity of theSeaway pipeline from the Cushing, Oklahoma, storage hub to400,000 barrels a day from 150,000 sometime in the first quarterof next year.

It is one of a number of pipeline projects aimed at curing abottleneck at the massive pipeline hub, which is expected toreduce deep price discounts for oil that travels there fromrapidly expanding U.S. and Canadian oil fields.

"We expect to bring another 250,000 barrels a day ofcapacity by the end of this year. But at some point, when wetwin that Seaway line, we'll start to see a relaxing of thisbasis differential between Cushing and the Gulf Coast," EnbridgePresident Al Monaco told reporters following a speech inToronto.

Monaco is slated to become CEO of the company, which movesthe bulk of Canadian oil exports to the United States, laterthis year.

Faster-than-expected growth in North American oil outputmeans his company's other pipelines could be at full capacity assoon as 2016 despite a recently announced C$3.2 billion ($3.1billion) expansion of its system, he said.

The company expects to complete the expansion of its NorthAmerican pipeline network in 2014, bulking up its 2 million bpdmainline, and tapping new refining markets in Quebec. Theplanned mainline expansion will add more than half a millionbarrels a day of new capacity within two years.

However, any relief for oil producers from the 2014expansion could be short-lived as forecasts call for productionfrom Canada alone to rise by more than half by the end of thedecade.

That could choke the system once more if lines such asEnbridge's planned 525,000 bpd Northern Gateway pipeline to thePacific Coast are not completed.

"I think we will be capacity-constrained going forward,probably in the range of 2016 and 2017," Monaco said. "There's anumber of opportunities out there to further expand capacity, Ithink one of them, frankly, that is a great opportunity isGateway ... And the advantage of Gateway, of course, is that itaccesses a very large market."

The C$5.5 billion Gateway project would offer Canadianproducers their first significant access to booming Asianmarkets and steer oil away from the glutted U.S. Midwest ifcompleted on schedule in 2017.

The project is supported by oil producers and the Canadiangovernment, but it is bitterly opposed by environmentalists andby many British Columbia aboriginal groups concerned aboutpotential oil spills. Even if the line is approved byregulators, court challenges could further delay construction.